Reaktionen an μ<sub>3</sub>‐verbrückenden Alkin‐Liganden auf Heterometallclustern

Bantel, Harald; Powell, Annie K.; Vahrenkamp, Heinrich

doi:10.1002/cber.19901230804

Cited by 22 publications

(1 citation statement)

References 25 publications

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“…We favor the second mechanism, as thermolysis of both alkenyl complex 6b and alkylidene complex 7b have all afforded the allenyl complex 8 in moderate yields. Finally, this transformation from vinylalkenyl to allenyl via the 1,3-H-migration is related conceptually to the conversion of an alkyne (HCCR) to a vinylidene (CCHR) on trinuclear clusters via a 1,2-H-shift 4 …”

Section: Discussionmentioning

confidence: 99%

Syntheses and Reactivity of Heterometallic Oxo−Acetylide Cluster Compounds. Skeletal Rearrangement and Conversion of Acetylide to Alkenyl, Alkylidene, and Allenyl Ligands on a WRe₂ Framework

Chi

Chen

et al. 1997

Organometallics

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Oxidation of the mixed-metal cluster Cp*WRe 2 (CCR)(CO) 9 (1, Cp* ) C 5 Me 5 ; R ) Ph and C(Me)dCH 2 ) with dioxygen in solution at 100 °C affords the oxo clusters Cp*W(O)Re 2 (CCR)-(CO) 8 , (2a, R ) Ph; and 2b, R ) C(Me)dCH 2 . Treatment of 2 with CO at 110 °C provides the clusters Cp*W(O)Re 2 (CCR)(CO) 9 (4), which revert back to 2 by removal of one CO upon thermolysis. Both compounds 2 and 4 contain an open triangular skeletal arrangement, a multisite bound acetylide ligand, and a terminal oxo ligand attached to the W atom. Complex 2a reacts with dihydrogen to form a mixture of three cluster complexes: the acetylide cluster Cp*WRe 2 (µ-O)(µ-H) 2 (CCPh)(CO) 6 (5a), alkenyl cluster Cp*W(O)Re 2 (CHCHPh)(CO) 8 (6a), and the alkylidene cluster Cp*W(O)Re 2 (µ-H)(CHCH 2 Ph)(CO) 8 ( 7a), which are formally produced by addition of two H 2 and elimination of two CO molecules, transferring one H 2 to the acetylide ligand and incorporation of one H 2 molecule to 6a, respectively. For the vinylacetylide compound 2b, it reacts with dihydrogen under similar conditions to furnish a mixture of the above mentioned clusters 5b, 6b, and 7b, together with a fourth allenyl cluster Cp*WRe 2 (µ-O)(CHCCMe 2 )(CO) 7 ( 8), which is probably produced through a 1,3-Hmigration on the alkenyl ligand CHdCHC(Me)dCH 2 in 6b. The X-ray structural analysis of these oxo cluster compounds, their spectroscopic data, and the mechanistic studies of the conversion from acetylide clusters 2, 4, and 5 to alkenyl clusters 6, alkylidene clusters 7, and allenyl cluster 8 are presented.

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Section: Discussionmentioning

confidence: 99%

Syntheses and Reactivity of Heterometallic Oxo−Acetylide Cluster Compounds. Skeletal Rearrangement and Conversion of Acetylide to Alkenyl, Alkylidene, and Allenyl Ligands on a WRe₂ Framework

Chi

Chen

et al. 1997

Organometallics

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Cotrimerizations of Acetylenic Compounds

et al. 2007

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The cyclotrimerization of acetylenic compounds is a useful method for the construction of three new bonds in a one‐step process. Although symmetry‐allowed, there is a paucity of examples of purely thermal [2+2+2] cycloadditions. The first example reported was in 1866, which was the cyclization of acetylene to benzene. High temperatures are required for this reaction and a mixture of products is formed. In 1948, Reppe discovered the first transition‐metal catalyzed version of this reaction in which nickel was used and substituted benzenes were formed. Since then catalysts based on transition metals, lanthanides, actinide, and aluminum have been developed for the cycloaddition of substituted alkynes to benzene derivatives. Many compounds can take part in the cyclization reactions to give four‐, five‐,six, or eight membered rings. Many of these reactions have found many applications in organic synthesis This chapter is devoted to early to late transition metal‐mediated cotrimerization of acetylenic compounds directed towards organic synthesis. It addresses the scope and generality of the reaction, as well as the current state of the art, with regard to region‐and stereoselectivities. In the context of selectivity, a mechanistic overview is provided. Inter‐and intramolecular versions of the cyclizations are presented with an emphasis on applications in synthesis. The literature up to mid‐2004 is covered.

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Activation of Organic Substrates on Multi-Metallic Sites of Transition Metal Polyhydride Clusters Having C5Me5 Groups as Auxiliary Ligands

Suzuki

2002

Eur. J. Inorg. Chem.

105

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An overview of the chemistry of the di‐ and trinuclear transition metal polyhydride complexes containing only C5Me5 groups as auxiliary ligands is presented. The synthesis of a series of η5‐C5Me5 polyhydride clusters and their reactivities centered about some typical examples of “multi‐metallic activation” including the cleavage of carbon−hydrogen bonds of alkanes, carbon‐carbon bond of cyclopentadiene, and carbon−carbon double bond of 1,1‐disubstituted alkenes, achieved on the reaction site of the polyhydride‐bridged clusters, are reported. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

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Reaktionen an μ₃‐verbrückenden Alkin‐Liganden auf Heterometallclustern

Cited by 22 publications

References 25 publications

Syntheses and Reactivity of Heterometallic Oxo−Acetylide Cluster Compounds. Skeletal Rearrangement and Conversion of Acetylide to Alkenyl, Alkylidene, and Allenyl Ligands on a WRe₂ Framework

Syntheses and Reactivity of Heterometallic Oxo−Acetylide Cluster Compounds. Skeletal Rearrangement and Conversion of Acetylide to Alkenyl, Alkylidene, and Allenyl Ligands on a WRe₂ Framework

Cotrimerizations of Acetylenic Compounds

Activation of Organic Substrates on Multi-Metallic Sites of Transition Metal Polyhydride Clusters Having C5Me5 Groups as Auxiliary Ligands

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Reaktionen an μ3‐verbrückenden Alkin‐Liganden auf Heterometallclustern

Cited by 22 publications

References 25 publications

Syntheses and Reactivity of Heterometallic Oxo−Acetylide Cluster Compounds. Skeletal Rearrangement and Conversion of Acetylide to Alkenyl, Alkylidene, and Allenyl Ligands on a WRe2 Framework

Syntheses and Reactivity of Heterometallic Oxo−Acetylide Cluster Compounds. Skeletal Rearrangement and Conversion of Acetylide to Alkenyl, Alkylidene, and Allenyl Ligands on a WRe2 Framework

Cotrimerizations of Acetylenic Compounds

Activation of Organic Substrates on Multi-Metallic Sites of Transition Metal Polyhydride Clusters Having C5Me5 Groups as Auxiliary Ligands

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Reaktionen an μ₃‐verbrückenden Alkin‐Liganden auf Heterometallclustern

Syntheses and Reactivity of Heterometallic Oxo−Acetylide Cluster Compounds. Skeletal Rearrangement and Conversion of Acetylide to Alkenyl, Alkylidene, and Allenyl Ligands on a WRe₂ Framework

Syntheses and Reactivity of Heterometallic Oxo−Acetylide Cluster Compounds. Skeletal Rearrangement and Conversion of Acetylide to Alkenyl, Alkylidene, and Allenyl Ligands on a WRe₂ Framework